<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
   <!--  写一个函数 求m-n之间数字的和？ -->
   <script>
var a = 5;
var n = 10;
var c=0;
for(m=a;m<=n;m++){
c+=m
}
console.log(c)


   </script>
</body>
</html>